Electrical Systems and Mechatronics (Commercial Vehicle Technology) 3662608375, 9783662608371

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Commercial Vehicle Technology

Michael Hilgers Wilfried Achenbach

Electrical Systems and Mechatronics

Commercial Vehicle Technology Series Editors Michael Hilgers, Weinstadt, Baden-Württemberg, Germany Wilfried Achenbach, HPCC2D-ENG, Daimler Trucks North America LLC, Portland, OR, USA

More information about this series at http://www.springer.com/series/16469

Michael Hilgers · Wilfried Achenbach

Electrical Systems and Mechatronics

Michael Hilgers Daimler Truck Stuttgart, Germany

Wilfried Achenbach Daimler Truck Portland, OR, USA

Commercial Vehicle Technology ISBN 978-3-662-60837-1 ISBN 978-3-662-60838-8  (eBook) https://doi.org/10.1007/978-3-662-60838-8 © Springer-Verlag GmbH Germany, part of Springer Nature 2021 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a specific statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained herein or for any errors or omissions that may have been made. The publisher remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Planung/Lektorat: Markus Braun This Springer Vieweg imprint is published by the registered company Springer-Verlag GmbH, DE part of Springer Nature. The registered company address is: Heidelberger Platz 3, 14197 Berlin, Germany

Preface

For my children Paul, David and Julia and my wife Simone, who share my passion for trucks.

I have worked in the commercial vehicle industry for many years. Time and again I am asked, “So you work on the development of trucks?” Or words to that effect. “That’s a young boy’s dream!” Indeed it is! Inspired by this enthusiasm, I have tried to learn as much as I possibly could about what goes into making commercial vehicles. During my tenure, I have discovered that you have not really grasped the subject matter until you can explain it cogently. Or to put it more succinctly. “In order to really learn, you must teach.” Accordingly, as time went on I began to write down as many technical aspects of commercial vehicle technology as I could in my own words. I very quickly realized that the entire project needed to be organized logically, and once that was in place the basic framework of this series of booklets on commercial vehicle technology practically compiled itself. This booklet deals with the mechatronics in the truck. The term mechatronics is explained comprehensively in the text. The short version in a nutshell: this booklet essentially describes the truck’s electronic systems and brakes. Readers who are studying this subject (students and technicians) will find this booklet to be a good entry point and as a result may discover that commercial vehicle technology is a fascinating field of work. In addition, I am convinced that this booklet will provide added value for technical specialists from related disciplines who would like to see the big picture and are looking for a compact and easy-to-understand summary of the subjects in question. My most important objective is to familiarize the reader with the fascination of truck technology and make it enjoyable to read. With this in mind, I hope that you, dear readers, have much pleasure reading, skimming and browsing this booklet. At this point, I would like to express my sincere appreciation to my managers and many colleagues in the trucks division of Daimler AG for their support in the completion vii

viii

Preface

of this series. Most importantly, the major contributors to this text are my colleagues from Daimler Trucks North America, namely Derek Rotz, Robert Heyburn and Michelle Footer, who enriched and filled this text with vital information and figures on truck technology typical for the North American market. A very big thank you to their magnificent work! My thanks also go to Springer Verlag for their kind cooperation, which led to the present result. Finally, I have a personal favor to ask. It is important to me that this work continue to expand and mature. Dear reader, I would greatly welcome your help in this regard. Please send any technical comments and suggestions to the following email address: [email protected]. The more specific your comments are, the easier it will be for me to understand its implications, and possibly incorporate them in future editions. If you discover any inconsistencies in the content or would like to express your praise, please let me know via the same email address. My wish is that everything is comprehensible and engaging. Happy reading! Stuttgart-Untertürkheim November 2019

Michael Hilgers

Contents

1 Electrical Systems and Mechatronics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Wiring Harness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.2 Power Supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.2.1 Network Management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.2.2 Starter Battery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.3 Lighting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 1.3.1 Monitoring the Lighting Function. . . . . . . . . . . . . . . . . . . . . . . . . . 11 1.3.2 Automated Light Functions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1.3.3 Interior Illumination. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 1.4 Horn and Other Acoustic Signals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 1.5 Mechatronic System Modules. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 1.5.1 Data Bus Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 1.5.2 Electronic Control Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 1.5.3 AUTOSAR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 1.5.4 Sensors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 1.5.5 Switches and Control Levers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 1.5.6 Actuators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 1.6 The Overall Mechatronic System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 1.6.1 Functional Concept . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 1.6.2 Architecture. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 1.6.3 Diagnostics and Flashing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 1.6.4 Electromagnetic Compatibility EMC . . . . . . . . . . . . . . . . . . . . . . . 25 1.7 Instruments and Displays. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 1.7.1 Main Instrument Panel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 2 Pneumatics System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29 3 Brake System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 3.1 Wheel Brake or Foundation Brakes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 3.1.1 Drum Brake. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 3.1.2 Disc Brake. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 ix

x

Contents

3.2 3.3 3.4 3.5 3.6 3.7 3.8 3.9 3.10

Brake Cylinder. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Parking Brake or Handbrake. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Pneumatic Brake System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Anti-Lock Braking System – ABS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 Traction Control, Traction Control System (TCS). . . . . . . . . . . . . . . . . . . . 46 Electronic Stability Program – ESP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 Braking the Trailer. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Other Brake Functionalities and Components. . . . . . . . . . . . . . . . . . . . . . . 49 Electropneumatic Brake. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

4 Advanced Driver Assistance Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 4.1 Advanced Driver Assistance Systems for Longitudinal Guidance . . . . . . . 53 4.2 Driver Assistance Systems for Lateral Guidance. . . . . . . . . . . . . . . . . . . . . 56 4.3 General Aids Through Driver Assistance Systems . . . . . . . . . . . . . . . . . . . 57 4.4 Driver Assistance Systems in Support of Visibility. . . . . . . . . . . . . . . . . . . 59 4.5 Autonomous Driving. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60 5 Telematic Systems. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 Comprehension Questions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67 Abbreviations and Symbols. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Index. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

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Electrical Systems and Mechatronics

Even the motor vehicle patented by Carl Benz in 1886 already included an electrical component: the battery with make-and-break ignition. The radio could be considered one of the first complex electrical systems, which was installed in US vehicles before the Second World War. The first true electronic systems with complex semiconductor circuits were implemented in engine controllers in the 1960s. Since then, the electrical and electronic systems in motor vehicles have become progressively more important. Many of the vehicle functions that are standard today are only possible with the aid of sophisticated electronics. It is estimated that about 90% of all innovations in motor vehicles rely on electronic systems [1]. Figure 1.1 shows how the number of electronic control units (ECUs) in trucks has increased in the period between the late 1980s and 2014. This indicates the increasing importance of electronics in motor vehicles. The importance of electronics will continue to grow in the future, but the absolute number of ECUs probably won’t. Due to the constraints of space requirements, complicated wiring, etc., the number of actual ECUs will not increase at all, or will only increase very slowly. Instead, the performance capability of each individual ECU will continue to increase, as it has done in the past. In addition, ECU functionality will be devolved to the sensors and actuators, which are already referred to widely as intelligent sensors and actuators. In the following sections, first the electrical infrastructure of the vehicle will be explained; then the mechatronic systems in a commercial vehicle will be described. Many components of the vehicle that are typically discussed under other headings can now quite legitimately be understood as mechatronic systems. For example, strictly speaking the hybrid, the start-stop function, the automated gearbox and even the engine itself are by definition mechatronic systems. But here we will apply the term as it is understood in everyday language in which the term mechatronics serves as a c­ atch-all

© Springer-Verlag GmbH Germany, part of Springer Nature 2021 M. Hilgers and W. Achenbach, Electrical Systems and Mechatronics, Commercial Vehicle Technology, https://doi.org/10.1007/978-3-662-60838-8_1

1

1  Electrical Systems and Mechatronics

Number of electronic control units

2

Year Fig. 1.1   Number of electronic control units (ECUs) in a European long-distance haulage truck in the last 25 years.

for the vehicle’s electronic data processing (EDP) infrastructure, the brake system, electronic brake and chassis systems, advanced driver assistance systems (ADAS) and infotainment.

1.1 Wiring Harness There will be many meters and several kilos of wiring installed in any given truck. There are wires used for supplying the necessary electrical power to the ECUs, sensors and actuators, and wires that serve to transmit signals. So a distinction can be made between the energy network (or power network, or powernet) and the communication network. Some sporadic attempts have been made to power supply and data over the same wire, similar to the solutions for building technology. However, the separation of communication and power supply is established as the more practicable approach. The wires inside a harness connect the units of the mechatronic system – that is to say the ECUs, the actuators and the sensors. The interface between the harness and the mechatronic component typically has the form of plug-in connectors. Standardized connectors do exist; there are also connectors that have been developed specifically for a given connection. The plug-in connector provides a connection that can easily be made and disconnected again. This is important when it comes to maintenance (parts replacement). The plug-in connector must be designed in such a way that it transmits the signals and/or the electrical power reliably and does not become disconnected unintentionally (i.e. loss of contact-type problems). Depending on their installation location, plugs and plug-in connectors must also be able to withstand high temperatures, aggressive medias, dirt, moisture and vibration.

1.2  Power Supply

3

Given the enormous number of variants, equipment options and vehicle lengths, essentially every vehicle has a unique wiring harness. In automotive production, one of two approaches may be adopted to deal with this diversity: In the first variant, harnesses are indeed assembled and installed in the vehicles specifically in association with a given purchase order. This means the harness only fits in the one specific vehicle for which it was made. The other methodology consists in defining several different standard harnesses. The vehicle is then fitted with the standard harness which is just sufficient to ensure the supply to the components in the vehicle. Accordingly, some vehicles then receive a harness in which wires are provided but do not serve in function in that particular vehicle. Thus, the fitting of unused wires is seen as worthwhile in order to reduce the number of variants.

1.2 Power Supply The power supply and distribution in medium-duty and heavy-duty trucks is a nominal 24 V DC voltage network in Europe and 12 V DC in the USA (more likely 28 and 14 V in real life). The voltage of the power supply is selected so as to ensure that it does not represent an electrical hazard for people. Due to the growing need for more electrical energy in the vehicle, the question is raised time and again as to whether the voltage should be increased to 42 or 48 V, for example, and there is justification for this. But as all components are available in the current voltage range, higher voltages have not been established yet in the automotive world. Some circuits in the onboard electrical system are defined in DIN 72552 [5]. For example, the permanent supply of voltage to the battery (i.e. positive terminal) is referred to as battery power or terminal 30. When the battery voltage is supplied as soon as the ignition is switched on, it is referred to as ignition power or terminal 15. Terminal 50 or crank power supplies voltage to the starter motor. Electrical power for the onboard electrical system is delivered by the alternator or the battery. The alternator is driven mechanically by the internal combustion engine, so it only supplies energy while the internal combustion engine is running. When the engine is not running, the battery is the only energy source. The alternator generates AC voltage, which is rectified. When the ignition is switched on, normally all electrical functions of the vehicle are available. The engine does not necessarily have to be running. The electronics system is awake. Depending on how it is equipped, the power consumption of a vehicle when it is awake is around 3 amps. These 3 amps are required simply to ensure that the ECUs are ready to communicate and function. If additional electrical functions on the vehicle are used, such as the radio or the lights, or if accessories are powered via the sockets (coffee machine or the like), power consumption increases correspondingly. The power consumption of certain consumers that are typically operated when the vehicle is stationary (as well) are shown in Table 1.1.

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1  Electrical Systems and Mechatronics

Table 1.1  Power consumption by various consumers that also run when the vehicle is stationary and place a load on the battery. Output in watts (W) (approx.)

Power consumption in amps (A) in a 12 V network (approx.)

Power consumption in amps (A) in a 24 V network (approx.)

Vehicle awake, full equipment

≈6 A

≈3 A

On-board electronics asleep

≈0.2 A

≈0.1 A

Low beams, halogen (one side)

75 W

≈6 A

≈3 A

Reading light

10 W

Storage compartment light

5 W

≈0.8 A

≈0.4 A

Windshield heater

1000 W

Radio

30 W

≈85 A

≈42 A

≈4 A

≈2 A

Refrigerator box (aver- 50 W age) depending on insulation and outside temperature Coffee machine

300 W

Microwave

750 W

≈0.4 A

≈2.5 A

≈24 A

≈60 A

≈0.2 A

≈1.25 A

≈12 A

≈30 A

If the engine is not running, power must be supplied by the battery. The total usable charge that can be drawn from a battery is specified in amp-hours Ah1. This charge is often also called the battery capacity. Typical battery capacities for commercial vehicles are in the order of 220 Ah for vehicles with high power requirements. Since a 220 Ah battery weighs over 50 kg (approx. 110 lbs), smaller trucks, trucks with minimal equipment and trucks used for particularly weight-sensitive tasks are equipped with batteries that have a lower capacity (100 Ah, 140 Ah or 170 Ah). With a power consumption of 6 amps (in the 12V case), this means that just in the awake state the vehicle electronics will drain a fully charged battery in a matter of a few days.2 To prevent this, the ECUs restrict their own activities when the ignition is

1For readers who are not well-versed in electrical terms: If a current of one amp (1 A) flows for an hour (1 h), this means that a charge of one amp-hour (1 Ah) is being drawn from the battery. If 2 amps flow for three hours, this means that 6 Ah have been drawn. Current in [Amperes] is defined as charge per unit time. Thus, current times time equals charge. 2If

more consumers are operated, the battery will be drained that much faster.

1.2  Power Supply

5

switched off: The vehicle goes into sleep mode. This organized powering down and up of the ECUs is called network management. Commercial vehicles in North America have a substantial challenge in starting heavy duty diesel engines in cold environments due to 12 V energy sources compared to 24 V in other parts of the world. The size of the engine is a big factor in determining how many and what size batteries are required. This often results in two to four 12 V batteries in parallel to meet cold cranking amp rating (CCA). In other scenarios, additional battery banks may be added for parked HVAC systems to help avoid idling.

1.2.1 Network Management When the vehicle is switched off (or ignition off), the electronics system attempts to power down the electrical and electronic systems as quickly as possible to save power and not drain the battery unnecessarily. However, the mechatronic system doesn’t shut down immediately. The electronics terminate any processes that are still running and certain data is saved in the ECUs. Only when all ECUs report that they are not waiting to send or receive data and all internal processes have been terminated, will the ECUs shut down. The electronic logic that orchestrates all this is called network management. Ultimately, the effect is that the vehicle electronics do not go to sleep until some time after the ignition has been switched off. Quiescent current Even after the vehicle ignition has been switched off, the vehicle must still be able to execute certain functions. For example, the onboard receiver for the remote control key must still be responsive so that the vehicle can be unlocked or locked. The alarm system, the clock and the tachograph need electrical energy. The alarm system (and the locking function) must also be able to actuate the vehicle’s horn and light systems. This is why many ECUs are wakable, meaning that they can be reactivated even when the ignition is switched off. For this purpose, the bus receivers of these ECUs must respond to a wake-up signal even when the ignition is switched off. These wakable ECUs need to be able to draw a small amount of power in the quiescent state, when the vehicle is deactivated as well, corresponding to a current of about 200 µA per unit. The whole vehicle needs a quiescent current (or standby current), roughly on the order of about 50 mA for a fully equipped vehicle.

1.2.2 Starter Battery The energy for starting the internal combustion engine is normally supplied by a device called the starter battery, or simply known as the battery. The battery for a large internal combustion engine needs very high currents for a short time. The lead accumulator

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1  Electrical Systems and Mechatronics

technology typically used for the battery excels in delivering high current and power for a short period of time. The battery supplies the consumers in the vehicle with electrical power even when the alternator does not, for example, when the engine is not running. And besides its electrical requirements, the battery must also be equal to the basic requirements of the truck. It must be able perform its duties at -30°C and 70°C and withstand the vibrations acting on any component that is mounted on the vehicle frame. Starter batteries are also called secondary batteries, which means they can be recharged, unlike primary cells, which cannot be charged a second time. When the internal combustion engine is running, the battery is recharged by the alternator. The starter battery must be able to continue working after many such recharging and discharging cycles; this is called cycle strength. The charging process works well or not so well, depending on the temperature. With conventional lead-acid batteries, charging takes place very slowly at low temperatures. Unfortunately, the battery is subjected to greater loads in winter and is repeatedly recharged much more slowly than in warm weather. This explains why battery problems occur more frequently in winter. During charging, the electrical energy that is fed to the battery is converted into chemical energy. In the inverse chemical reaction the stored energy is released again as electrical energy. There are many material pair combinations that are currently used in batteries or being researched for future use. A large number of material pairs are being evaluated as part of the discussion surrounding electric and hybrid vehicles [4]. As to the battery, the lead accumulator has represented the de facto standard for decades. It is fairly tolerant with regard to handling, it can withstand the thermal stresses inside the vehicle (i.e. does not need active cooling) and it is relatively inexpensive to produce. The lead acid battery is capable of delivering the high currents needed for the starting operation. The chemical reaction takes place between lead, lead oxide and sulfuric acid. The reaction for delivering electric current (discharging) takes place as follows. At the battery’s negative terminal, which consists of a lead plate, the lead is oxidized by the sulfuric acid, forming lead sulfate (Eq. 1.1):

Pb + H2 SO4 → PbSO4 + 2e− + 2H+

(1.1)

At the same time at the positive terminal—a lead oxide plate—the lead oxide is reduced to form lead sulfate (Eq. 1.2):

PbO2 + H2 SO4 + 2e− → PbSO4 + 2O2− + 2H+

(1.2)

The overall reaction can be expressed in summary with the Eqs. 1.1 and 1.2 as shown in Eq. 1.3:

Pb + PbO2 + 2H2 SO4 → 2PbSO4 + 2H2 O + electrical energy

(1.3)

Accordingly, in a lead accumulators’ cells lead and lead oxide are transformed into lead sulfate. And the sulfuric acid is consumed. As a result, a fully charged starter battery

1.2  Power Supply

7

Electron flow

Sulfuric acid in high concentration